Photoelectric cell light ray condenser



oct. 2o, 1931. W, EBELING 1,828,399

PHOTOELECTRIC CELL LIGHT RAY GONDENSER Filed Sept. 18. 1930 @ma 5 EBEL /Ng vlo APatented Oct. 20, 1931l UNITED STATI-:s

"PATENT OFFICE i CHARLES W. EBELING, OF N'EW YORK, N. Yj., ASSIGNOB T0 GENERAL TALKING PICTURES conrona'rIoN, oiil Nnwxonx, N. Y., A CORPORATION or nnnnwnnn PHOTQIFELEC'IBIG CELL LIGHT RAY CONDENSE Application illed September 18, i930. Serial No. 482,828.

The present invention relates to a photoelectric cell light ray condenser, one ob] ect of which is. to condense the rays of lightA after the same has passed through the sound track offthe film and before the same impinges the photoelectric cfell thus insuring higher eiliciency in the action from the cell due to the concentration of the beam of light theret has been found Ain practise in the reproducing of sound wherein a film rovided with a sound track is acted upon y1 a beam of li ht generated by an exciter lamp and directer?v through an optical system upon the film,

5 that in many cases the rays from said beam 'of light after passing through the' to an aperture behind which is disposed the photoelectric cell has a tendency to disperse or' in other words there is a wide angle of disperw sion of the light ra sbehind the lm and therefore the most e cient results can be obtained by condensing the rays that are finally received by the hotoelectric cell.y In fact,

eriments con ucted have shown a gain of e 2a lig t intensit of ap roximately 40% when v clearly a condensing ens has 30 pact bundle as it were, so that concentrated rays are brought into contact with the photoelectric cell.v A

' In order that the present invention may be understood, attention is invited to the accompanying drawings in which p Figure 1 is a diagrammatic View of an optical arrangement now employed in sound reproducing apparatus, an particularly of a type used with talking pictures.

igure 2 is a similar view wi hthe present invention in use.

Figu

lens carrying member mounted therein. v`

Referring to drawin and more particularly to Figure 1 thereo the numeral 3 designates an exciter lamp, 4 an optical system, and 5 a slit block unit, a film 6 provided with theusual sound track not shown either of the variable density or variable area type being en interposed between the film and the photoelectric cell, or in fact v re 3 is a detailed cross sectional view. through a slit block unit showing the present" fect the photoelectric cell 10, all of usual construction. It will thus be seen that after the beam passes the film that there is a Wide angle of dispersion between theA lines 8 and 8', and

that therefore a considerable volume of the beam has no eect upon the photoelectric cell 10. y

In order to prevent this Wide angle of dispersion of the light ra s as shown in Figure 2 a' tube 12 is removab y mounted within the bore 11 and carries condensing lens 13 which thus receives the light rays 14 and causes the same to be directed as illustrated by the dotted lines so as to impinge upon the photoelectric cell 1Q to produce a gain in light intensity. Y n

.In practise it has been found as above set forth that vvith the lens 13 properly placed a' unit ain of 25 db, which represents a gain in li t intensity of approximately 40%.

at is claimed is: The combination with a slit block unit having afilm guiding surface with ana i rture j there through, a cylindrical bore eading 

